Conventionally, a diesel throttle opening is reduced depending on rich spike in deceleration such that a pressure within a cylinder is controlled to be equal to or lower than a predetermined pressure corresponding to a temperature within the cylinder at an compression end (for example, see Patent Document 1). On the other hand, there is known a technique of differentiating the phases of two intake valves for enhancing the fluidity of the intake air within the cylinder to improve the combustion (for example, see Patent Document 2).